Cyclone separator



March 10,- 193 J. H. KEENAN CYCLONE SEPARATOR Filed Aug. 30, 1933 Z Ifk8 2 Sheets-Sheet l INVENTOR Mam ATTORNEY March 10,

1936. J. H. KEENAN CYCLONE SEPARATOR Filed Aug. 30, 1933 2 Sheets-Sheet2 l2 9 u 7 :T I

INVENTOR ATTORNEY Patented Mar. 10, 1936 UNITED STATES Joseph H. Keenan,Hoboken, N. 3., asslgnor to Jabez Burns & Sons, Inc., New York, N. Y., acorporation of New York Application August 30, 1933, Serial No. 687,401

Claims.

This invention relates to improvements in devices for separatingparticles of denser substance from liquid or gas streams by swirling thestream and its particles in a free or constrained vortex. I shall referto all such devices, whether for c'om-' pletely separating particles andstream or merely for concentrating the particles withina portion of ductof round or approximately square cross-seciii The common type of cycloneseparator consists of the following parts: a cylinder into which theparticle-laden stream is introduced through a tion, the outside wall ofthe duct being tangent to the cylinder wall at entrance; a conicalchamber below the cylinder for collecting or leading off the separatedmaterial; a central outlet pipe, attached to the top of the cylinder andprojecting'down some distance into it, leading directly to the;

atmosphere or tea duct.

There are, of course, many variations on this common type of design. Insome cases the inside wall of the incoming stream, instead of theoutside wall, is made tangent to the cylinder. This arrangement. usuallyinvolves a departure from the usual circular cross-section of thecylinder toward a spiral cross-section. In some cases there completelyfllls the vortex chamber, (that is, it is not bounded at the top by aliquid surface) there is a pressure gradient, the pressure decreasingtoward the center of the vortex. This pressure gradient provides theradially inward accelerations to the stream which are necessary to theswirling motion. If, as in the usual cyclone separator, the streamleaves the cylinder or separating chamber through a central hole atthetop and passes directly to the atmosphere or tea duct then the minimumdrop in static pressure across the most perfect collector of this typewould be the pressure gradient integrated along a line passing throughthe vortex center between theinlet opening and the rim of the outlethole.

The pressure drop along the streampath in a vortex results in anincrease in the kinetic energy of the stream which, except for frictioneflfects, is an essentially reversible process; that is, the kineticenergy could, presumably, be reduced again to the original or entrancemagnitude with a rise in pressure equivalent (except for friction) tothedrop experienced in the separating vortex.

My invention includes devices for recoveringa large part of the pressuredrop through the separating chamber byreducing the velocity of the Insome designs guide vanes stream after it leaves the separating cylinderin a properly designed chamber or passage. In its preferred form itsconsists of two parallel horizontal plates, substantially circular inplan view and of about the same diameter as the separating cylinder. Thelower plate has a central hole which fits the outlet pipe of theseparating cylinder. The fluid stream passes from the outlet pipe of theseparating cylinder into the space between the two plates and flowsspirally outward until it reaches the atmosphere. If the device isintended to discharge into a duct instead of into the atmosphere, ascroll-type passage may be arranged around the perimeters of the topplates which will lead off the stream tangentially into a duct.

The stream enters this top passage with an angular momentum per unittime which is smaller than the angular momentum at the entrance to theseparating'cylinder by the wall friction moments only. This angularmomentum results in a vortex in the top passage similar to the one inthe separating chamber except that the direction of flow is spirallyoutward instead of spirally inward. The usual vortex pressure gradientis established in this top passage and the fluid stream flows from thelow pressure region at the small radius from the center of the vortex atn which it enters to the higher pressure region at the large radius atwhich it leaves. The pressure drop across the whole device is thussmaller than the pressure drop across the ordinary cyclone separator bythe pressure rise which occurs in the top chamber.

The process of increasing the pressure along the path of a fluid streamby reducing its velocity I shall hereafter refer to as diflusion, andthe passage or chamber in which the process'is carried out I shall calla diffuser, a diffusing passage, or a diflusing chamber. A diiIuser isessentially a reversed nozzle since in a nozzle the stream increases invelocity and decreases in pressure in the direction of flow while in adifiuser the stream decreases in velocity and increases in pressure inthe direction of flow.

It is interesting to follow the pressure distribution through aseparator fitted with a diffusing passage which discharges to theatmosphere. The pressure in the exit opening is necessarily atmospheric.The pressure in the connecting hole between the separating cylinder andthe diflfusing passage is lower than atmospheric because the vortex inthe diffusing passage sets up a higher pressure at its periphery than inthe center. If this were an ordinary separator the pressure in this holewould be atmospheric, and the inlet pressure, and all other pressureswhich the blower of the system must pump against, would be higher by anamount equal to the vacuumobtained .in--the connecting hole of mydevice. I I

The utility of this device consists in the reduction in powerconsumption in the fan or compressor which provides the pressuredifi'erential for overcoming the various frictional resistances in thepath of the stream. It is obvious that any device which reduces thepressure drop in any part of the flow path will reduce the power inputto the fan almost in direct proportion for the same rate of fluid flow.

I am aware that some manufacturers of cyclone separators design the topof the separator so that the fluid leaves the central exit pipetangentially and in the direction of rotation. This results in a limitedutilization of the kinetic energy of the stream leaving the exit pipe,but it does not involve the compression of the stream to higher pressureby reducing velocity. Neither sort may be emphasized by pointing out thein herent reversibility of my combination. A separator may be fittedwith a diffusing passage and anoutlet scroll, the dischargecross-section of which may be made equal to the inlet area of theseparating cylinder. If a stream of frictionless fluid were introducedinto the separating cylinder at a certain pressure it would leavevtheoutlet scroll at the same pressure. "Across an ordinary separator, onthe other hand, thepressure of the fluid would have decreased by theintegrated pressure gradient through the separating vortex. In this newdesign the fluid flow could just as well have been reversed indirection, entering through the top scroll opening and leaving throughthe opening in the lower cylinder wall. The diflusing passage has nowbecome the separating chamber, and the separating chamber has become thedififusing passage. Such reversal of flow would be impossible in theordinary separator because the entering fluid in the reversed case,having no rotation, would produce no vortex and would do no separating.

This invention can be modified by inserting vertical guide vanes in thediffusing passage to aid the diifusion process or to reduce the lengthof the fluid path through the'diflusion passage.

In the accompanying drawings: Fig. 1 shows my invention in its simplestform and arranged to discharge the stream directly to the atmosphere.

Fig.2isatransversesectiononline2-2 of Fig. 1.

Fig. 3 shows experimental data on the saving realized from the use ofthe device shown in Fig. l. V a

Fig. 4 shows my invention with two modifications, first, a conicalconnecting piece between the cylinder outlet pipe and the diffusingpassage and, second, guide vanes in the diffusing passage to aiddiifusion.

Fig.5isatransversesectiononlineS-iot Fig. 4. 1

Fig. 6 shows my invention arranged to discharge into a duct.

Fig.7isatransversesectiononline1-4I of Fig. 6.

Fig.8isaseparatorarrangedtopermitthe stream to flow in eitherdirection.-

Flg.9isatransversesectiononline i-l oi Fig. 8.

Fig. 10 shows a modification of Fig. l with conical instead of flatdiffusing plates.

The separator shown in Figs. 1 and 2 comprises vertical cylinder l inwhich the denser particles are separated from the fluid stream whichenters through approach pipe 2, lower conical hopper 3 for collecting orleading oil the denser separated material, discharge pipe 4 throughwhich the stream passes on its way to diffusing passage 8, which isbounded by circular plates 6 and I resting on supports 8. Plates 6 and Ineed not be horizontal but may be formed into substantially parallelcones with apexes at the top or at the bottom of the cone. Slightdepartures from parallelism between 6 and I will not necessarily destroythe efifectiveness of the diifusion passage and in some instances mightbe advantageous.

' The distance between plates (or cones) 6 and I for minimum pressuredrop across the entire device must be determined in each instance byexperiment. Fig. 3 shows experimentally determined pressure dropsplotted against distance between plates 6 and I for a separator, similarto that shown in Figs. 1 and 2, the separating cylinder of which was 72inches diameter and the outlet pipe 27 inches diameter. The ordinate ispressure drop in inches of water, the abscissa is distance betweenplates 6 and I in inches. Line Illa shows the pressure drop for theseparator with only a weather shield over the outlet pipe. Line lllbshowsthe pressure drop for the same flow through the same separatorfltted with plates 6 and 1. A maximum gain of about 30% is realized inthis case when the plates are two inches apart.

The separator shown in Figs. 4 and 5 is similar to that shown in Figs. 1and 2 except for conical connecting piece 9 and guide vanes I0.Connecting piece 9 guides the fluid stream more smoothly into thediflfusing passage and reduces the eddy disturbances which may be causedby the sharp corner between discharge pipe 4 and plates 6 shown inFig. 1. The connecting piece need not, of course, be conical inshape-but may have a curved cross-section. The relative ease .with whichthe conical piece may be manufactured will recommend it even abovedesigns which might give slightly smoother flow. The guide vanes aredesirable to promote diffusion under certain circumstances, particularlyin cases where the tangential component of the velocity would otherwisebe high where the fluid passes out from between the plates.

In Figs. 6 and 7 is shown a separator with diffusing passage I l fittedwith scroll II. The scroll collects the stream leaving the diffuser andleads it to exit opening I; which is approximately of thesamecross-section area as separator inlet H. A duct may be connected to.the scroll at I 3 to lead the stream oil to other apparatus or to anoutlet pipe.

A separator arranged for flow in either direction is shown in Figs. 8and 9. It comprises lower cylinder I5 and upper cylinder I6 connected bycentral pipe I! and conical pieces It. The lower cylinder is fitted withconical hopper I! to lead oil or tocollect separated material. The uppercylinder is fitted with conical hopper 2B for the same purpose. Hopper20 surrounds pipe I I and through which separated material may pass into'15 ,vided with acentral the hopper. Similarly in the top cylinder isfltted plate 25 around the edge of which is left clearance space 26.Plates 22 and 25 are not essential to my invention, but they aiddiflusion when diffusion is occurring in their respective cylinders. Inthe absence of plates 22 and 25 the fluid in the hopper, being retardedby wall friction may be reduced in velocity to the point where itskinetic energy is inadequate to permit it to flow outward against the,pressure gradient. A reverse flow inward would then be set up within thehopper. Fluid flowing inward must ultimately be carried outward again byfriction drag from the main diifusing stream, and this process reducesthe momentum of the diffusing stream and reduces the rise in pressurerealized in the diffusion process. Plates 22 and 25 prevent transfer ofmomentum from the main stream to the fluid in the hopper. The lowercylinder is provided with opening 21 and the upper with opening 28 ofequal area. Both openings may be connected with ducts.

Now, if the fluid stream is led into opening 21 separation of denserparticles will occur in the vortex set up in cylinder the stream willpass from cylinder I5 through pipe I I to cylinder IS in which it willflow outward against the vortex pressure gradient to opening 28. Thedevice will work equally well if the direction of flow is reversed, thestream entering opening 28 and leaving through opening 21, separationoccurring in cylinder l6 and diil'usion in cylinder IS.

The device shown in Figs. 8 and 9 may be used in cases where separationof denser particles is desired from a stream which flows alternately inopposite directions, as in certain regenerative processes in industry.

Fig. 10 shows a somewhat better design for outdoor use than Fig. 1 inwhich plates 36 and 31 are coned instead of flat asare plates 6 and 1 inFig. 1, but the operation is the same.

The invention claimed is:

1. A difluslng passage comprising two substantially parallel andhorizontal plates in combination with a cyclone separator, including a.separating cylinder and a centrally disposed exit pipe, the lower platebeing in the form of an annulus supported above the top of theseparating cylinder and attached to the exit pipe of the separatingcylinder.

2. A difl'using pasage comprising two substantially parallel andhorizontal plates separated'by vertical guide vanes in combination witha cyclone separator, including a separating cylinder and a centrallydisposed exit pipe, the lower plate being in the form of an annuluswhich is attached to the exit pipe of the separating cylinder.

3. A diflusing passage comprising two substantially parallel conicalplates in combination with a cyclone separator, the lower cone beingprohole, and being attached to separating cylinder so that is concentricwith the exit said conical plates being close together to insure theexit pipe of the the hole in the cone pipe of the cylinder, disclosedsubstantially difiusion.

4. A diflusing passage comprising two substantially parallel plates, aperipheral chamber surrounding these plates, communicating with thespace between them and open at one point on the periphery whereconnectionvmay be made with a duct, in combination with a cycloneseparator, including a separating cylinder and a centrally disposed exitpipe, the lower of the two plates being provided with a central hole,and being attached tightly to the exit pipe of the separating cylinderso that the hole in the plate is concentric with the exit pipe of thecylinder, the upper plate extending over and beyond the hole in thelower plate a sufllcient distance to insure diffusion.

5. A cyclone separator consisting of two vortex chambers each having aperipheral opening and placed one above the other on a common centerline, the chambers communicating with each other through a central holeor pipe, with a chamber at the bottom of the lower vortex chamber forcollecting or leading off separated material, and an annular chamberattached to the bottom of the upper vortex chamber for collecting orleading oiif separated material, whereby the fluid stream may flow ineither direction through the separator with effective separation.

6. The combination with a cyclone separator having a cylindricalseparating chamber, a tangential inlet for dust-laden air, means forcollecting material separated from the air in said chamber, and acentrally disposed exit pipe for the air from said chamber, of means forreducing the velocity and increasing the pressure of the air dischargedfrom said exit pipe comprising a lower plate connected to the end of thepipe above the top of said separating chamber and an upper plateoverlying the lower plate and the pipe whereby to reduce the pressuredrop in the flow path and reduce the power input.

7. The combination with a cyclone separator having a cylindricalseparating chamber, a tangential inlet and a centrally disposed exitpipe, of a difiuser comprising a pair of superposed plates ofsubstantially the same diameter as said separating chamber, the lowerplate being in the form of an annulus attached to the exit pipe of saidseparating chamber above the top of said separating chamber.

8. The combination with a cyclone separator having a cylindricalseparating chamber, a tangential inlet and a centrally disposed exitpipe, of a diffuser comprising a pair of superposed cones ofsubstantially the same diameter as said separating chamber, the lowercone being in the form of anannulus attached to the exit pipe of saidseparating chamber, said cones being disposed substantially fusion.

9. The combination wlth a cyclone separator having a cylindricalseparating chamber, a tangential inlet and a centrally disposed exitpipe, of a diifuser comprising a pair of superposed plates ofsubstantially the same diameter as said separating chamber, the lowerplate being in the form of an annulus attached to the exit pipe of saidseparating chamber, and vertical guide vanes arranged between saidplates to promote diffusion.

10. The combination with a cyclone separator having a cylindricalseparating chamber, a tangential inlet and a centrally disposed exitpipe, of a diil'user comprising a pair of superposed plates ofsubstantially the same diameter as said separating chamber, the lowerplate being in the form of an annulusattached to the exit pipe of saidseparating chamber, and a scroll connecting the peripheries of saidplates and having an exit opening of approximately the samecross-sectional area as the inlet of said separating chamber.

JOSEPH H. KEENAN.

close together to'insure difcm rzcm or Wm, I Patent No. 2; 033, 7o. QMarch 10; 1936 JOLSEPH a. m mz.

It is hereby certified that error appears in the printed specification0: the above numbered patent requiring correction as follows: Page 3,first column, line 66, claim 3, for "disclosed" read disposed; and thatthe said Letters Patent should be read with this correction therein thatthesame ma conform to the record of the case in the Patent Office.

signed and sealed this 21st day of April, A. n. 1935.

Leslie Frazer (Seal) Acting Commissioner of Patents.

